Lock



Nov. 11, 1924- M. .c. MAXWELL ET Al.

LOCK

Filgd Aug. 14,

Patented Nov. ll, 1924.

te ve MAXWELL C. MAXWELL ANI) GIIARLES .LE-DIN, Oli STAMFORB,CONNECTICT, AS-

SIGNORS Tol THE YALE c TO'WNE MANUFACTURING COMANY, 0F STAMFORD, CON-NECTICUT,

LOCK.

Application led August 14, 1923. Serial No. $57,275.

To all whom t may concern.'

Be it known that we, MAXWELL C. MAX- WELL and CHARLES LEDIN, citizens ofthe United States, and residents of Stamford,

in the county of Fairfield and State of Connecticut, have inventedcertain new and useful Improvements in Locks; and we do hereby declarethe following to be a full, clear, and exact description of theinvention, such as will enable others skilled in the art to which itappertains to make and use the same.

This invention relates to improvements in locks,-one object of theinvention being to provide means whereby the operation of thebolt-operating cam will be blocked, or prevented from effectualoperation by the insertion of a tool, in the event attempt be made topull or twist the cylinder of the lock from its connection with the backplate of a rim lock and the door so that access might be had to theroll-back for operating the same to withdraw the bolt with the use of atool.

A further object is to so construct the back cover-plate of a rim lockthat it will become distorted in the event that attempt be made to pullor twist the cylinder of the lock from its position and prevent theeffectual throw of the roll-back cam.

With these and other objects in view, the invention consists in certainnovel features of construction and combinations of parts as hereinafterset forth and pointed out in the claims.

In the accompanying drawings Figure l is a face view of a backcoverplate for a rim lock and showing an application of ourimprovements.

Figure 2 is a sectional view on the line 2-2 of Figure 1.

Figure 3 is a sectional view (with the rollback in elevation) on theline 3-3 of Figure l.

Figure 4 is a face vi'ew of a back-plate showing a slight modilication.

Figure 5 is a sectional view, on the line 5-5 of Figure 4.

Figure 6 is a sectional view, partly in elevation, on the line 6-6 ofFigure 4, and

Figures 7 and 8 are views showing another form of construction.

A sheet metal back or cover plate for a rim lock is shown at l and isprovided with suitable holes 2 for the accommodation of fastening meanswhich secure the cover plate to a lock casing.

At approximately the centerof the plate l, a suitable opening isprovided for the accommodation of a roll-back 3 having a roll-bacli camor bolt operating member 4 connected therewith as is usual. in types oflock such as those to which our improvements relate. The plate l is'provided in proximity to the mounting of the roll-back cam with holes 5for the accommodation of bolts (not shown) which secure a lock cylinderin place. Four such holes are shown and either the upper or the lowerpair of holes may be utilized for the accommodation of such securingbolts.

The cover plate l is weakened in such manner that in the event attemptbe made to pull or twist the lock cylinder from the door, a portion ofsaid plate will be so distorted as to change the angle of the mountingof the roll-back to such an extent that the roll-back cam will becaused-to engage the face of the plate and be prevented thereby frombeing moved sufficiently to withdraw the bolt of the lock,-the plateitself thus acting as blocking means for the roll-back cam. The plate lmay be weakened for the purpose above stated by providing approximatelyT-shaped slots 6 near respective sides or above and below the mountingof the roll-back cam as indicated in Figure l. Instead of makingT-shaped slots as above described in the plate l, said plate may beprovided with diametrically opposite, approximately semi-circular slots7, as illustrated in Figure 4.

The plate 1 may be weakened in the manner shown in Figures 7 and 8 forthe purpose hereinbefore explained, by slotting or slitting said platein a manner to provide tongues 8 at respective sides of that portion ofthe plate to which the cylinder of the lock is to be secured. This maybe accomplished by shearing down the metal of the plate in the form ofthe tongues 8 and then bending back the metal to its former positionlevel with the surrounding surface.

Having fully described our invention what we claim as new and desire tosecure by Letters Patent, is

l. In a lock, the combination of a back or cover plate provided with anormally rigid part adapted for the reception of cylinder lock fasteningmeans, a bolt operatlng member carried by said part, said part beingdisplaceable relatively to the body oit the plate by the application ettorce to a cylinder lool: when secured thereto, to render the boltoperating meinber inoperable.

2. ln a lock, the combination ot a back or cover plate having adistortable portion adapted for the reception ot securing means for a.cylinder lock, and a bolt operating means carried by the distortableportion oit said cover plate.

3. ln a lock, the combination ot a back or cover plate adapted to have acylinder lock secured thereto, a bolt operating cani carried by saidplate, and means whereby that portion of the cover plate to which thecylinder loch may be secured Will bev distorted it said cylinder loch beforcibly pulled or twisted and thus, prevent. the effective throw ot thebolt operating earn.

4L. In a lock, a back or cover plate adapted to have a lock cylindersecured thereto, said cover plate being` weakened adjacent to that partto which the lock cylinder is to be secured, whereby said port-ion maybecoine distorted by the application ot torce.

ln a lock. a back or oo'fer plate adapted to hafe a cylinder locksecured thereto, said cover plate being` cnt in proximity to thatportion ol the plate to `which 'the lool: cylinder is to be secured7whereby said pon tion ot the plate will be subject to distortion uponthe application ot force.

6. ln a lock, the combination of a bach or cover plate, a roll-back Cainmounted therein, said cover plate having slots at respective sides ofthe n'iounting' of the rollback cam and also having holes in the areabetween said slots for the recept-ion of fastening means tor a cylinderlool;7 whereby that portion ot the plate which 'receives 'the cylinderfastening means may be distorted.

ln testimony whereofa *we have sign-ed this specification in thepresence ot two subscribing Witnesses.

BLEU/WELL C. MAXWELL. CHARLES LEDlN.

Witnesses A. DoUGLAs DALTON, CHARLES A. BERRY.

